<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
  <meta charset="UTF-8">
  <title>JavaScript 运算符</title>
</head>
<body>
<h2>字符串和数字的相加</h2>
<p>数字和字符串相加，会返回字符串。：</p>

<p id="demo"></p>

<script>
  var x = 7 + 8;
  var y = "7" + 8;
  var z = "Hello" + 7;
  document.getElementById("demo").innerHTML =
          x + "<br>" + y + "<br>" + z;
</script>
</body>
</html>